The present disclosure relates to a vacuum pumping system comprising a vacuum pumping arrangement.
FIG. 4 shows a vacuum pumping system 100 comprising a vacuum pumping arrangement 102 for evacuating gas from a vacuum processing chamber 104, such as that of a solar panel, flat panel, LED or semi-conductor processing tool. The vacuum pumping arrangement comprises a primary pump 106 and a secondary pump 108 arranged in series. The primary, or roughing, pump 106 exhausts at atmosphere and may be a dry pump such as a screw, roots, claw or scroll pump. The secondary, or high vacuum, pump 108 is connected to the vacuum chamber 104 and exhausts to the inlet of the primary pump. The secondary pump is typically a turbo-molecular pump or mechanical booster pump.
The vacuum pumping system 100 comprises a foreline vacuum line 110, which can be any suitable conduit such as a pipe or hose, connecting the vacuum chamber 102 to the vacuum pumping arrangement 104 and the inlet of the secondary pump 108. A further foreline conduit 112 connects the exhaust of the secondary pump 108 to the inlet of the primary pump 106. An exhaust line conduit 114 connects to the exhaust of the primary pump 106.
The vacuum pumping system may further comprise an abatement apparatus 116 for removing noxious substances from the gas evacuated from the vacuum chamber 104. A valve 118, such as a bypass valve, diverts gas to a gas storage facility 120 during abatement apparatus downtime. The exhaust line conduit 114 is connected to the valve 118 for ducting gas to either the abatement apparatus 116 or the storage facility 120.
Gas exhausted from the process chamber 104 typically contains contaminants in addition to process gases. The contaminants may comprise particulates, such as silica dust; or liquid precursors, such as TEOS. In the vacuum pumping system shown in FIG. 4, the vacuum processing chamber 104 is located above the vacuum pumping arrangement 102 and the vacuum line 110 ducts gas in a generally downwards direction to the inlet of the vacuum pumping arrangement and through the arrangement to the exhaust line. Contaminants present in the gas stream drop under gravity into the vacuum pumping arrangement causing damage or reduced operability. A trap may be provided in the vacuum line 110 between the vacuum chamber and the pumping arrangement assisting in the collection and protection of the vacuum pumping arrangement, but are generally located high above the vacuum pump and are ergonomically difficult to service.
The exhaust of the vacuum pumping arrangement is at or proximate floor level. The inlet of the abatement apparatus is generally located in an elevated position, relative to the exhaust of the pumping arrangement, and accordingly the exhaust line 114 is often of considerable length. The extended length of the exhaust line may comprise such disadvantageous features as U-bends and horizontal pipework that can provide an abundance of locations for process by-products to deposit. In order to prevent condensation of exhausted substances it is generally required that valve 118 is heated, as shown, which contributes to the cost of ownership of the vacuum pumping system.
It is an object of the invention to provide an improved vacuum pumping system.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.